Objective To review the osteoimmunomodulatory effects and related mechanisms of inorganic biomaterials in the process of bone repair. Methods A wide range of relevant domestic and foreign literature was reviewed, the characteristics of various inorganic biomaterials in the process of bone repair were summarized, and the osteoimmunomodulatory mechanism in the process of bone repair was discussed. Results Immune cells play a very important role in the dynamic balance of bone tissue. Inorganic biomaterials can directly regulate the immune cells in the body by changing their surface roughness, surface wettability, and other physical and chemical properties, constructing a suitable immune microenvironment, and then realizing dynamic regulation of bone repair. Conclusion Inorganic biomaterials are a class of biomaterials that are widely used in bone repair. Fully understanding the role of inorganic biomaterials in immunomodulation during bone repair will help to design novel bone immunomodulatory scaffolds for bone repair.
ObjectiveTo explore the feasibility of three-dimensional (3D) bioprinted adipose-derived stem cells (ADSCs) combined with gelatin methacryloyl (GelMA) to construct tissue engineered cartilage.MethodsAdipose tissue voluntarily donated by liposuction patients was collected to isolate and culture human ADSCs (hADSCs). The third generation cells were mixed with GelMA hydrogel and photoinitiator to make biological ink. The hADSCs-GelMA composite scaffold was prepared by 3D bioprinting technology, and it was observed in general, and observed by scanning electron microscope after cultured for 1 day and chondrogenic induction culture for 14 days. After cultured for 1, 4, and 7 days, the composite scaffolds were taken for live/dead cell staining to observe cell survival rate; and cell counting kit 8 (CCK-8) method was used to detect cell proliferation. The composite scaffold samples cultured in cartilage induction for 14 days were taken as the experimental group, and the composite scaffolds cultured in complete medium for 14 days were used as the control group. Real-time fluorescent quantitative PCR (qRT-PCR) was performed to detect cartilage formation. The relative expression levels of the mRNA of cartilage matrix gene [(aggrecan, ACAN)], chondrogenic regulatory factor (SOX9), cartilage-specific gene [collagen type Ⅱ A1 (COLⅡA1)], and cartilage hypertrophy marker gene [collagen type ⅩA1 (COLⅩA1)] were detected. The 3D bioprinted hADSCs-GelMA composite scaffold (experimental group) and the blank GelMA hydrogel scaffold without cells (control group) cultured for 14 days of chondrogenesis were implanted into the subcutaneous pockets of the back of nude mice respectively, and the materials were taken after 4 weeks, and gross observation, Safranin O staining, Alcian blue staining, and collagen type Ⅱ immunohistochemical staining were performed to observe the cartilage formation in the composite scaffold.ResultsMacroscope and scanning electron microscope observations showed that the hADSCs-GelMA composite scaffolds had a stable and regular structure. The cell viability could be maintained at 80%-90% at 1, 4, and 7 days after printing, and the differences between different time points were significant (P<0.05). The results of CCK-8 experiment showed that the cells in the scaffold showed continuous proliferation after printing. After 14 days of chondrogenic induction and culture on the composite scaffold, the expressions of ACAN, SOX9, and COLⅡA1 were significantly up-regulated (P<0.05), the expression of COLⅩA1 was significantly down-regulated (P<0.05). The scaffold was taken out at 4 weeks after implantation. The structure of the scaffold was complete and clear. Histological and immunohistochemical results showed that cartilage matrix and collagen type Ⅱ were deposited, and there was cartilage lacuna formation, which confirmed the formation of cartilage tissue.ConclusionThe 3D bioprinted hADSCs-GelMA composite scaffold has a stable 3D structure and high cell viability, and can be induced differentiation into cartilage tissue, which can be used to construct tissue engineered cartilage in vivo and in vitro.
Objective To investigate the biocompatibil ity of silk fibroin nanofibers scaffold with olfactory ensheathing cells (OECs) and to provide an ideal tissue engineered scaffold for the repair of spinal cord injury (SCI). Methods Silk fibroin nanofibers were prepared using electrospinning techniques and were observed by scanning electron microscope (SEM). Freshly isolated OECs from SD rats purified by the modified differential adherent velocity method were cultured. The cells at passage 1 (1 × 104 cells/cm2) were seeded on the poly-l-lysine (control group) and the silk fibroin nanofibers (experimental group) coated coversl ips in Petri dish. At desired time points, the morphological features, growth,and adhesion of the cells were observed using phase contrast inverted microscopy. The OECs were identified by the nerve growth factor receptor p75 (NGFR p75) immunofluorescence staining. The viabil ity of OECs was examined by l ive/dead assay. The prol iferation of OECs was examined by MTT assay. The cytotoxicity of the nanofibers was evaluated. Results The SEM micrographs showed that the nanofibers had a smooth surface with sol id voids among the fibers, interconnecting a porous network, constituted a fibriform three dimensional structure and the average diameter of the fibers was about (260 ± 84) nm. The morphology of OECs on the experimental group was similar to the cell morphology on the control group, the cells distributed along the fibers, and the directions of the cell protrusions were in the same as that of the fibers. Fluorescence microscopy showed that the purity of OECs was 74.21% ± 2.48% in the experimental group and 79.05% ± 2.52% in the control group 5 days after culture. There was no significant difference on cell purity between two groups (P gt; 0.05). The OECs in the experimental group stained positive for NGFR p75 compared to the control group, indicating that the cells in the experimental group still maintained the OECs characteristic phenotype. Live/dead staining showed that high viabil ity was observed in both groups 3 days after culture. There was no significant difference on cell viabil ity between two groups. The prol iferation activity at 1, 3, 5, 7, and 10 days was examined by MTT assay. The absorbency values of the control group and the experimental group had significant differences 3 and 5 days after culture (P lt; 0.05). The relative growth rates were 95.11%, 90.35%, 92.63%, 94.12%, and 94.81%. The cytotoxicity of the material was grade 1 and nonvenomous according to GB/T 16886 standard. Conclusion Silk fibroin nanofibers scaffold has good compatibility with OECs and is a promising tissue engineered scaffold for the repair of SCI.
The presence of thrombus on the surface of blood-contacting biomaterials in clinical practice can significantly impact both the longevity of the biomaterials and the overall survival prognosis of patients. The administration of anticoagulant and antiplatelet medications may heighten the risk of systemic bleeding. Developing biomaterials with anti-thrombogenetic properties and enabling localized anti-thrombosis may offer a solution to these challenges. The development strategies for anti-thrombogenetic biomaterials can be categorized into three main approaches based on the mechanisms of thrombus formation on biomaterial surfaces: altering physical and chemical properties, designing coatings containing or releasing active substances, and promoting endothelialization. However, due to the intricate and interconnected nature of these mechanisms, biomaterials constructed using a single approach may not effectively prevent thrombus formation. The collaborative intervention of various mechanisms can facilitate the development of biomaterials with enhanced blood compatibility.
ObjectiveTo summarize the research progress of interfacial tissue engineering in rotator cuff repair.MethodsThe recent literature at home and abroad concerning interfacial tissue engineering in rotator cuff repair was analysed and summarized.ResultsInterfacial tissue engineering is to reconstruct complex and hierarchical interfacial tissues through a variety of methods to repair or regenerate damaged joints of different tissues. Interfacial tissue engineering in rotator cuff repair mainly includes seed cells, growth factors, biomaterials, oxygen concentration, and mechanical stimulation.ConclusionThe best strategy for rotator cuff healing and regeneration requires not only the use of biomaterials with gradient changes, but also the combination of seed cells, growth factors, and specific culture conditions (such as oxygen concentration and mechanical stimulation). However, the clinical transformation of the relevant treatment is still a very slow process.
Objective To review the research progress on bone repair biomaterials with the function of recruiting endogenous mesenchymal stem cells (MSCs). Methods An extensive review of the relevant literature on bone repair biomaterials, particularly those designed to recruit endogenous MSCs, was conducted, encompassing both domestic and international studies from recent years. The construction methods and optimization strategies for these biomaterials were summarized. Additionally, future research directions and focal points concerning this material were proposed. Results With the advancement of tissue engineering technology, bone repair biomaterials have increasingly emerged as an ideal solution for addressing bone defects. MSCs serve as the most critical “seed cells” in bone tissue engineering. Historically, both MSCs and their derived exosomes have been utilized in bone repair biomaterials; however, challenges such as limited sources of MSCs and exosomes, low survival rates, and various other issues have persisted. To address these challenges, researchers are combining growth factors, bioactive peptides, specific aptamers, and other substances with biomaterials to develop constructs that facilitate stem cell recruitment. By optimizing mechanical properties, promoting vascular regeneration, and regulating the microenvironment, it is possible to create effective bone repair biomaterials that enhance stem cell recruitment. Conclusion In comparison to cytokines, phages, and metal ions, bioactive peptides and aptamers obtained through screening exhibit more specific and targeted recruitment functions. Future development directions for bone repair biomaterials will involve the modification of peptides and aptamers with targeted recruitment capabilities in biological materials, as well as the optimization of the mechanical properties of these materials to enhance vascular regeneration and adjust the microenvironment.
In order to enhance the anticoagulant properties of decellularized biological materials as scaffolds for tissue engineering research via heparinized process, the decellularized porcine liver scaffolds were respectively immobilized with heparin through layer-by-layer self-assembly technique (LBL), multi-point attachment (MPA) or end-point attachment (EPA). The effects of heparinization and anticoagulant ability were tested. The results showed that the three different scaffolds had different contents of heparin. All the three kinds of heparinized scaffolds gained better performance of anticoagulant than that of the control scaffold. The thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (APTT) of EPA scaffold group were longest in all the groups, and all the three times exceeded the measurement limit of the instrument. In addition, EPA scaffolds group showed the shortest prepared time, the slowest speed for heparin release and the longest recalcification time among all the groups. The decellularized biological materials for tissue engineering acquire the best effect of anticoagulant ability in vitro via EPA heparinized technique.
With the continuous progress of materials science and biology, the significance of biomaterials with dual characteristics of materials science and biology is keeping on increasing. Nowadays, more and more biomaterials are being used in tissue engineering, pharmaceutical engineering and regenerative medicine. In repairing bone defects caused by trauma, tumor invasion, congenital malformation and other factors, a variety of biomaterials have emerged with different characteristics, such as surface charge, surface wettability, surface composition, immune regulation and so on, leading to significant differences in repair effects. This paper mainly discusses the influence of surface charge of biomaterials on bone formation and the methods of introducing surface charge, aiming to promote bone formation by changing the charge distribution on the surface of the biomaterials to serve the clinical treatment better.
Ligaments are dense fibrous connective tissue that maintains joint stability through bone-to-bone connections. Ligament tears that due to sports injury or tissue aging usually require surgical intervention, and transplanting autologous, allogeneic, or artificial ligaments for reconstruction is the gold standard for treating such diseases in spite of many drawbacks. With the development of materialogy and manufacturing technology, engineered ligament tissue based on bioscaffold is expected to become a new substitute, which can lead to tissue regeneration by simulating the structure, composition, and biomechanical properties of natural tissue. This paper reviewed some recently published in vitro and animal researches focusing on ligament tissue engineering, then evaluated the properties and the effects on tissue repair and reconstruction of fiber structure scaffolds, multi-phase interface scaffolds and bio-derived scaffolds designed by bionic principle and made of different materials, manufacturing techniques and biological factors. Finally, summarization followed by the prospection for future development direction of biological scaffolds in ligament tissue engineering research is given.
Infectious bone defects are usually caused by trauma, surgical infections, or chronic osteomyelitis, and represent a complex and intractable clinical challenge in the field of orthopaedics. Biological scaffolds can achieve synergistic repair of defects by loading antibiotics for controlled release to inhibit bacteria, providing support for cell proliferation and differentiation to promote bone regeneration, and carrying factors or stem cells to enhance vascularization. They possess incomparable advantages over traditional treatment methods in the management of infectious bone defects, and the selection of appropriate biological scaffolds in clinical practice needs to be tailored to the type of defect and the severity of infection. Therefore, this article elaborates on the application and research progress of biological scaffolds in the treatment of infectious bone defects.